Droopy leaves on marijuana plant

A question from a fellow grower:

my plants are about 5 weeks old . they have been growing real good but
now the leaves are starting to droop . can anyone tell me what might
cause that to happen ?

I don’t think it is an under or over watering issue because when the
lights come on they perk up and are all nice and perky and then a few
hours before the lights go off they droop down. I checked the Ph and it
is high, and I am changing that with Ph Down in the water, could that be
a reason they start drooping a few hours before the light goes off?
Also, there are 10, half are nice and big and the other half are small
and it is the same seed. Could this be a ph issue?

also the the leaves on some of them are curling . especially at the top
of the new bud spots . they are autoflower plants and started budding
about a week ago . please let me know what you think and if you can help

Here’s some reasons that often causes drooping leaves,also some pics of the problem would be helpful.

  1. Temps are too high- your leaf edges will be standing up as well if this the primary issue.

Over and/or under feeding- this relates to nute levels, not frequency
of watering. If the solution is too high, they will droop, if it is too
low they will droop, but for different reasons.
3. Over and/or under
watering- if the balance is off, the plants will have trouble adjusting
& will likely droop at each application/withholding.
4. Humidity
& air circulation- if is very dry or very damp, they will droop.
Tied to this is something called vapor pressure deficit (vpd), but that
is just too much info.

Russ1 has some good info for you, also, absolutely the pH being off can cause all sorts of problems, droopy leaves, twisting leaves, curling leaves, dying leaves, and it can absolutely slow and stunt growth.

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I’ve been adjusting the PH in the water before i water my plants. Most of the leaf curling has went away. Now they look pretty good until a couple hours before the lights go off and then they start drooping again. And when the light comes back on they perk right back up. I have ten of them. They’re autoflowers. Six of them are pretty big and still getting bigger. But the other four don’t seem to be growing much and those four are drooping the most. But the PH and everything else is the same in all of the plants. I can’t figure out why they’re doing that. If you have any suggestions please let me know. Thank You.

Are you sure the pH is good at the root zone? You need to monitor this as well as what you feed them, pH can build up in the soil and be different from what you are watering them with of feeding them, especially if you have run into a pH problem that has been around for a little while.

BTW, I’m not totally sure if this might be most of, or part of what is going on, but plants droop during the dark period. Plants can develop their own “sleep rhythms”, if you will, and they will sometime droop a little before they are expecting the dark period.

I have a PH tester for the soil. that’s how i knew the PH was high. I tested the soil and the PH was good for the first five or six weeks. And then the PH got real high in the soil for some reason. So now I’m making sure the PH in the water is good before i water them. And like i said the curling in the leaves has pretty much gone away but the small plants are still drooping and aren’t growing very much. Maybe it’s too late for the small ones, I don’t know. They have about 30 days left till they’re finished.

If you mean by too late that they will never catch up to the others, yes, especially with autoflowers.

With regular photoperiod plants, you can extend the veg light cycle to give them time to get to the size you want, this means the overall time until harvest will be longer but the harvest will be bigger, but you can’t do anything like that with autos.

BTW, if you are using tap water that is a bit hard, or mineral water with high pH’s, as I said above, the pH can build up in the soil. That is why you need to pH the water as well when watering them.

Yeah, that’s what I figured. I’ve grown before but this is the first time with autoflowers. And I am making sure the PH in the water is correct. That’s how I got the PH level to come down in the soil and the leaves to stop curling. I guess I’ll just have to ride it out with this crop. Thanks for all the info. I appreciate it.

Last night I let my plants stay out beyond sunset, and the temps drop significantly at night. When I brought them back in after a couple of hours for their light box, all were drooping, as if they were chilly and trying to stay warm. This morning they’re all reaching for the sky again.

Any suggestions on what to do? Applied some LST… took off really well. A day or 2 later she has started to droop. About 5 weeks in…

Looks like it could be a water problem, as in too much or too little. That is a common cause of leaf droop. As well as fertilizer mixture and humidity too high or low. If you recently went to Flowering from Veg the light height from the plants could be a problem. Can’t say for sure but that might be good places to start.

I would airrate the soil by using a chop stick, stick in dirt to make air pockets,maybe check to see if your soil is compacted, if so could be no oxygen going to leaves, food for thought

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that sir is a proper necropost

I apologize for the stupid question, but how do I create a new post? I’ve seen threads that say to scroll to the bottom of a topic and click to add a new topic, but I don’t see that option. I have some specific issues with pictures that I’d love some advice on, and I cannot for the life of me figure out how to make a post to get some help.